Three Mitogen-Activated Protein Kinases Inhibit Insulin Signaling by Different Mechanisms in 3T3-L1 Adipocytes
| Autor: | Tomoichiro Asano, Yukiko Onishi, Motonobu Anai, Miho Abe, Yoshitomo Oka, Takehide Ogihara, Hideyuki Sakoda, Midori Fujishiro, Yasushi Fukushima, Yukiko Gotoh, Hideki Katagiri, Nobuhiro Shojima, Hiraku Ono, Masatoshi Kikuchi |
|---|---|
| Rok vydání: | 2003 |
| Předmět: |
MAPK/ERK pathway
medicine.medical_specialty Insulin Receptor Substrate Proteins Blotting Western MAP Kinase Kinase 1 MAP Kinase Kinase 7 MAP Kinase Kinase 6 Protein Serine-Threonine Kinases Mitogen-activated protein kinase kinase Gene Expression Regulation Enzymologic Mice Phosphatidylinositol 3-Kinases chemistry.chemical_compound Endocrinology Transduction Genetic Insulin receptor substrate Internal medicine Adipocytes medicine Animals Insulin Phosphorylation Molecular Biology Phosphoinositide-3 Kinase Inhibitors Mitogen-Activated Protein Kinase Kinases biology Tumor Necrosis Factor-alpha GRB10 Intracellular Signaling Peptides and Proteins Tyrosine phosphorylation 3T3 Cells General Medicine Phosphoproteins Precipitin Tests IRS2 Cell biology Insulin receptor Glucose chemistry Calcium-Calmodulin-Dependent Protein Kinases Mutagenesis Site-Directed biology.protein Insulin Resistance Mitogen-Activated Protein Kinases Signal Transduction |
| Zdroj: | Molecular Endocrinology. 17:487-497 |
| ISSN: | 1944-9917 0888-8809 |
| DOI: | 10.1210/me.2002-0131 |
| Popis: | TNFα, which activates three different MAPKs [ERK, p38, and jun amino terminal kinase (JNK)], also induces insulin resistance. To better understand the respective roles of these three MAPK pathways in insulin signaling and their contribution to insulin resistance, constitutively active MAPK/ERK kinase (MEK)1, MAPK kinase (MKK6), and MKK7 mutants were overexpressed in 3T3-L1 adipocytes using an adenovirus-mediated transfection procedure. The MEK1 mutant, which activates ERK, markedly down-regulated expression of the insulin receptor (IR) and its major substrates, IRS-1 and IRS-2, mRNA and protein, and in turn reduced tyrosine phosphorylation of IR as well as IRS-1 and IRS-2 and their associated phosphatidyl inositol 3-kinase (PI3K) activity. The MKK6 mutant, which activates p38, moderately inhibited IRS-1 and IRS-2 expressions and IRS-1-associated PI3K activity without exerting a significant effect on the IR. Finally, the MKK7 mutant, which activates JNK, reduced tyrosine phosphorylation of IRS-1 and IRS-2 and IRS-associated PI3K activity without affecting expression of the IR, IRS-1, or IRS-2. In the context of our earlier report showing down-regulation of glucose transporter 4 by MEK1-ERK and MKK6/3-p38, the present findings suggest that chronic activation of ERK, p38, or JNK can induce insulin resistance by affecting glucose transporter expression and insulin signaling, though via distinctly different mechanisms. The contribution of ERK is, however, the strongest. |
| Databáze: | OpenAIRE |
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